EMS Viewpoint
by Jeff Lindsey
Sponsored by Masimo
05/14/2012

Hypothermia: Our treatment is our prevention


This has been one of the warmest winters on record. Yet, hypothermia continues to be a threat to our patients, especially our trauma patients.

Even in the sunshine state of Florida, hypothermia is a threat to those exposed to the elements. Trauma patients are exceptionally vulnerable to hypothermia. Patients experiencing shock, burns, and head and spinal injuries are most susceptible.

We know that hypothermic patients are never considered dead until they are warm and dead. Due to the mammalian reflex, our body shunts the blood from our periphery to our core body organs, perfusing them in order to maintain life.

It also slows perfusion to conserve and preserve our vital organs. Therefore, when the body begins to warm, the patient’s body begins to restore perfusion to areas where blood was shunted away.

In a traumatic patient, perfusion is compromised in a patient presenting with shock. In burn patients, we need to be concerned with fluid loss among other problems, and in spinal and head injuries, the regulation system of our body has been compromised.

In cardiac arrest patients (non-traumatic) with return of spontaneous circulation (ROSC), induced hypothermia is considered the standard of care.

However, in contrast, in patients with traumatic brain injuries, there are no significant differences in outcome with induced hypothermic treatment.

This trial (Daniel Limmer, Michael O’Keefe, 2009, Emergency Care) is thought to draw a final conclusion to a now nearly decade-long investigation as to whether hypothermia improves TBI outcomes. 

We remain in need of effective TBI therapies, but researchers will have to look elsewhere as temperature control is clearly not the answer. Therefore, we know hypothermia is not the friend of a patient with a traumatic injury.

The best method to any problem is preventing it from happening in the first place. Our treatment in this situation mirrors our prevention practice.

However, the sooner we recognize the potential for the trauma patient to suffer from hypothermia, the better we can prevent the trauma patient from becoming more hypothermic.

In order to prevent the loss of body temperature, we need to know how we lose heat. We know that our body regulates our temperature; however, it is susceptible to lose heat through conduction, convection, radiation, evaporation, and respiration. 

Conduction
If our patient is lying on a cold surface (a fall victim laying on a cold floor) or immersed in a cold environment (a dive injury with patient in the water), they are going to continue to lose heat. The body’s contact with a cold surface is going to lose heat quickly. A patient in water will lose heat up to 25 times faster.

You can prevent the patient from becoming hypothermic by putting a warm item, such as a warm blanket, between the patient and the surface, or remove the patient from the cold surface altogether.

Convection
The loss of heat through convection is when air or water passes over the body and carries away the heat. Getting the patient out of the environment prevents further harm. If the patient is entrapped in a vehicle, creating a shield with blankets or personnel to shield the patient from the wind will help in reducing the loss of heat through convection.

Radiation
A person loses heat merely by being in the environment , mainly through the head and neck. In addition, if the person has a head and neck injury, the patient’s perfusion to this area is more susceptible. Making sure the patient is covered with warm blankets will not only assist in the treatment of the patient, but also prevent the patient from losing more heat.

Evaporation
Evaporation occurs when the body perspires. In the efforts of our treatment of keeping the patient warm, we can also be detrimental to the patient by creating an environment so warm that they begin to perspire and then lose heat through perspiring. The patient then becomes hypothermic.

Respiration
When we exhale, we exhale warm air. If the ambient air of the incident scene is cold, the warm air the patient is exhaling can cause hypothermia for the patient.  In addition, the rate and depth of the patient’s respiration has an effect on them. In most cases, a traumatic patient needs oxygen.

Providing oxygen will not only provide the patient with the much-needed oxygenation, but also help prevent hypothermia from their respiration.

Summary
Induced hypothermia in a ROSC patient is the standard of care. Hypothermic patients are never dead until they are warm and dead. Hypothermic traumatic patients are in jeopardy.

Our treatment for hypothermia is also our prevention for our trauma patient. It does not matter where you are in the country; if the environment is cooler than our body temperature, hypothermia is possible.

There are five ways our body loses heat. As part of our treatment for these patients, we should immediately take into consideration the prevention of hypothermia for our trauma patients. Tunnel visioning can be detrimental to the prevention of hypothermia in a trauma patient. Treating hypothermia in a trauma patient is the prevention of further hypothermia.

References

S. Andrew Josephson, MD, Hypothermia Ineffective in Traumatic Brain Injury Posted: 01/27/2011; AccessMedicine from McGraw-Hill © 2011 The McGraw-Hill Companies retrieved from http://www.medscape.com/viewarticle/735959 on March 18, 2012

Daniel Limmer, Michael O’Keefe (2009) Emergency Care, 11th Edition Upper Saddle River, NJ
 

Dr. Jeffrey Lindsey is an Assistant Professor in Emergency Health Services at George Washington University. He retired from the fire service as the Fire Chief for Estero Fire Rescue. Additionally, he serves as the education coordinator for 24-7 EMS and author for Brady Publishing. He is an experienced leader, educator, lecturer, author, and consultant in emergency services. Dr. Lindsey earned his doctorate and master's degree in Curriculum and Instruction from USF.He holds a bachelor's degree in Fire and Safety Engineering from the University of Cincinnati, and an associate in paramedicine from Harrisburg Area Community College. Dr. Lindsey has more than 29 years of diverse experience in the emergency services industry.

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